Hey guys, I think it's about time to talk to you guys about a very important concept in chess: the 'discovered' or 'revealed' attack.
A discovered attack is when one piece moves, and behind it lays an attacking piece. These attacks should never be overlooked, as they are extremely powerful and can be potentially game-changing.
Here's a (very) simple example of what I mean:
Obviously that attack doesn't actually achieve much, as the queen can easily be moved away, but when a revealed attack is combined with a check or another attack, then things get interesting. Let's say we were to change that bishop to be on a white square... how can white now use that discovered attack for something far more devastating?
Now the full power of the revealed attack is seen. There are a few different ways which revealed attacks can be used, we'll look at a few examples here:
As we saw above, discovered attacks on pieces with check are very powerful, as the king must deal with the check before any other threat can be dealt with. The piece moving can give check, or there can also be a discovered check, which is equally powerful.
In the example above, when the bishop moves, it will also put the king in check at the same time, meaning that the bishop now has one 'free attack' anywhere it likes, even if it is unprotected. Pretty scary, as that attack can be extremely powerful. Here's another example:
It's sometimes even worth sacrificing a piece for the sake of a discovered attack... see if you can figure out this one:
So by now you've probably realised that discovered attacks with check are incredibly devastating if used effectively, so as a rule of thumb it's important to remember to never let your king be in a position where it could be the victim of a discovered check or a discovered attack.
Obviously sometimes it will be difficult to spot discovered attacks from pieces that check you, but for now make it a habit to never put your king behind the attacking line of an enemy piece if there's only their pieces in between them. Even if it may look safe, a few moves later you could easily find yourself in a lot of trouble (as you'll see later when we look at a game I played against Harry).
Another kind of discovered attack is when you attack two pieces at once, and then one must fall.
And another example:
So now that we've established that discovered attacks and discovered checks are a very powerful tactics (even grandmasters respect the power of this small tactic!), the thing you guys have to be aware of is not letting yourself fall victim of them, and eventually start using them yourself if possible. There will always be a few that slip under your radar, but at least knowing about them and their potential for game-changing plays will help you out with your tactical vision.
From here I'll give you guys a couple of examples of some real games which use these, and a few puzzles which you can try out for yourselves.
A very common use of the discovered attack to win a game very early on is in the Petroff defence. I lost to this in the state finals last year to some year 9, which I'm still pissed off about. You guys can have a look for yourselves so you can not make the same mistake I did, and maybe even try this on some people who try to play the Petroff against you.
Now let's give you a try at finding a discovered attack.
Here's a game I recently played against Dom that's slightly more complicated.
Here's a game I recently finished against Harry which he unfortunately let himself become a victim of the discovered check, despite thinking it was safe (sorry Harry, but again, this is educational).
In the example above, even though it seemed irrelevant which direction he moved his king because he had a mate in one anyway, I was still able to find a way to use my 'free move' from the discovered check to place my knight in a powerful position. Although that would've been hard to see coming, and it was mostly luck on my end, it just emphasises the point that if possible, you should never let your king be put in a position which it can be the victim of a discovered check.
Here's a fairly extreme example of multiple forced discovered checks, called a 'windmill'.
So that's about it from me about discovered attacks, if you want to do some more advanced study on them, I'd really recommend reading this article by the famous chess teacher and international master Silman: http://www.chess.com/article/view/the-dreaded-discovered-attack. It gets pretty advanced, but it still may give you an idea of how discovered attacks and checks can be used (albeit subtly) to win games even at a professional level.